Much of this area is mountainous and unsuitable for urbanization. Tokyo has numerous outlying islands, which extend as far as 1850 km from central Tokyo. There are several national parks within Tokyo. Over eight million people live within Tokyo. Tokyo is one of the three world finance "command centers”. Tokyo is a major international finance center, houses the headquarters of several of the world's largest investment bank and insurance companies, and serves as a hub for Japan's transportation, publishing, and broadcasting industries.